Publications by authors named "Yeup Yoon"

47 Publications

Semi-Automated Cell Panning for Efficient Isolation of FGFR3-Targeting Antibody.

Int J Mol Sci 2021 Jun 9;22(12). Epub 2021 Jun 9.

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, Korea.

Phage display technology is a widely used practical tool for isolating binding molecules against the desired targets in phage libraries. In the case of targeting the membrane protein with its natural conformation, conventional bio-panning has limitations on the efficient screening of the functionally relevant antibodies. To enrich the single-chain variable fragment (scFv) pools for recognizing the natural conformation of the membrane targets, the conventional bio-panning and screening process was modified to include the semi-automated cell panning protocol. Using FGFR3-overexpressing patient-derived cancer cells, biotin-X-DHPE was introduced and coupled to Streptavidin-coated magnetic beads for use in the solution-phage bio-panning procedure. The resulting clones of scFv were compared to the diversity of the binding region, especially on CDR-H3. The clones enriched further by cell-based panning procedure possessed a similar binding site and the CDR-H3 loop structure. The resulting antibodies inhibited cell growth and induced target degradation. This process may be a useful tool for screening biologically related antibodies that recognize natural conformational structure on cell membrane protein. Furthermore, cell-based panning has the potential to further expand to a high-throughput screening (HTS) system and automation process.
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http://dx.doi.org/10.3390/ijms22126240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229736PMC
June 2021

Characterization of Gut Microbiome in Korean Patients with Metabolic Associated Fatty Liver Disease.

Nutrients 2021 Mar 21;13(3). Epub 2021 Mar 21.

Samsung Medical Center, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.

Metabolic associated fatty liver disease (MAFLD) is a new concept where the presence of both fatty liver and metabolic abnormality are necessary for diagnosis. Several studies have reported that altered gut microbiome is closely associated with metabolic diseases and non-alcoholic fatty liver disease. However, the studies on MAFLD population are scarce. This prospective study aimed to identify differences in gut microbiome between patients with MAFLD and healthy controls in Korean population. In this study, patients with MAFLD and age, sex-matched healthy controls were included, and their stool samples were collected. Taxonomic composition of gut microbiota was analyzed using 16S ribosomal ribonucleic acid pyrosequencing. Twenty-two MAFLD patients and 44 healthy controls were included. Taxonomic diversity was lower in patients with MAFLD in the aspect of alpha and beta diversity. The differences were also found at phylum, class, family, and genus levels between the two groups. Phylum , family , genus abundance was significantly increased and genus was significantly decreased in patients with MAFLD. In addition, butyrate-producing bacteria were decreased and ethanol-producing bacteria were increased in patients with MAFLD. The composition of gut microbiome was different between MAFLD and healthy controls in Korean population. This could offer potential targets for therapeutic intervention in MAFLD.
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http://dx.doi.org/10.3390/nu13031013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004024PMC
March 2021

cIRCR201-dPBD, a Novel Pyrrolobenzodiazepine Dimer-Containing Site-Specific Antibody-Drug Conjugate Targeting c-Met Overexpression Tumors.

ACS Omega 2020 Oct 29;5(40):25798-25809. Epub 2020 Sep 29.

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06355, Republic of Korea.

c-Met, as a receptor expressed on the cell membrane, contributes to the growth and metastasis of tumors, as well as angiogenesis, mainly through the hepatocyte growth factor (HGF)/c-Met axis during tumor progression. Although several c-Met inhibitors, including small molecules and monoclonal antibody inhibitors, are currently being investigated, their clinical outcomes have not been promising. Development of an antibody-drug conjugate (ADC) against c-Met could be an attractive therapeutic strategy that would provide superior antitumor efficacy with broad-spectrum c-Met expression levels. In the present study, site-specific drug-conjugate technology was applied to develop an ADC using the human-mouse cross-reactive c-Met antibody and a prodrug pyrrolobenzodiazepine (PBD). The toxin payload was uniformly conjugated to the light-chain C-terminus of the native cIRCR201 antibody (drug-to-antibody ratio = 2), as confirmed using LC-MS. Using a high-throughput screening system, we found that cIRCR201-dPBD exhibited varying sensitivities depending on the expression levels of c-Met, and it induced receptor-mediated endocytosis and toxin-mediated apoptosis in 47 different cancer cell lines. cIRCR201-dPBD also showed significant antitumor activity on the -amplified cancer cells using in vivo xenograft models. Therefore, cIRCR201-dPBD could be a promising therapeutic strategy for tumors with c-Met expression.
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http://dx.doi.org/10.1021/acsomega.0c03102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557224PMC
October 2020

Double-filtered leukoreduction as a method for risk reduction of transfusion-associated graft-versus-host disease.

PLoS One 2020 26;15(3):e0229724. Epub 2020 Mar 26.

Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunwan University School of Medicine, Seoul, Korea.

Background: Transfusion-associated graft-versus-host disease (TA-GvHD) is caused by leukocytes, specifically T cells within a transfused blood product. Currently, the prevention of transfusion-associated graft-versus-host disease is performed by irradiation of blood products. With a sufficient reduction of leukocytes, the risk for TA-GvHD can be decreased. With consistent advances in current state-of-the-art blood filters, we herein propose that double filtration can sufficiently reduce leukocytes to reduce the risk for TA-GvHD.

Materials: Thirty RBC concentrates were filtered with leukocyte filters, followed by storage at 1-6 oC for 72 hours, and then a second filtration was performed. Residual leukocytes in the double-filtered RBC units (n = 30) were assessed with flow cytometric methods, and an additional assay with isolated peripheral blood mononuclear cells (PBMCs) (n = 6) was done by both flow cytometric methods and an automated hematology analyzer. Quality of the RBCs after filtration was evaluated by hematological and biochemical tests. In vitro T cell expansion was performed using anti-CD3/CD28-coated Dynabeads or anti-CD3 (OKT3). In vivo experiment for GvHD was performed by using NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice.

Results: Double-filtered blood products showed residual leukocyte levels below detection limits, which calculated to be below 1200-2500 cells per blood unit. In vitro expansion rate of T cells showed that 6x103 and 1x103 cell-seeded specimens showed 60.8±10.6 fold and 10.2±9.7-fold expansion, respectively. Cell expansion was not sufficiently observed in wells planted with 1x102 or 10 cells. In vivo experiments showed that mice injected with 1x105 or more cells cause fatal GvHD. GvHD induced inflammation was observed in mice injected with 1x104 or more cells. No evidence of GvHD was found in mice injected with 103 cells.

Conclusions: Our study suggests that additional removal of contaminating lymphocytes by a second leukodepletion step may further reduce the risk for TA-GvHD.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229724PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098637PMC
June 2020

Pharmacogenomic landscape of patient-derived tumor cells informs precision oncology therapy.

Nat Genet 2018 10 27;50(10):1399-1411. Epub 2018 Sep 27.

Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

Outcomes of anticancer therapy vary dramatically among patients due to diverse genetic and molecular backgrounds, highlighting extensive intertumoral heterogeneity. The fundamental tenet of precision oncology defines molecular characterization of tumors to guide optimal patient-tailored therapy. Towards this goal, we have established a compilation of pharmacological landscapes of 462 patient-derived tumor cells (PDCs) across 14 cancer types, together with genomic and transcriptomic profiling in 385 of these tumors. Compared with the traditional long-term cultured cancer cell line models, PDCs recapitulate the molecular properties and biology of the diseases more precisely. Here, we provide insights into dynamic pharmacogenomic associations, including molecular determinants that elicit therapeutic resistance to EGFR inhibitors, and the potential repurposing of ibrutinib (currently used in hematological malignancies) for EGFR-specific therapy in gliomas. Lastly, we present a potential implementation of PDC-derived drug sensitivities for the prediction of clinical response to targeted therapeutics using retrospective clinical studies.
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http://dx.doi.org/10.1038/s41588-018-0209-6DOI Listing
October 2018

Innovative Distribution Priorities for the Medical Devices Industry in the Fourth Industrial Revolution.

Int Neurourol J 2018 Jul 31;22(Suppl 2):S83-90. Epub 2018 Jul 31.

Department of Medical Device Management and Research, SAIHST, Sungkyunkwan University, Seoul, Korea.

Purpose: This study aimed to set priorities for improving the medical device distribution structure and to suggest an innovative improvement plan for the distribution structure using the analytic hierarchy process (AHP) method, focusing on stakeholders in the medical device industry.

Methods: This study conducted a survey with 35 specialists using the AHP method, which is a multiple-criteria decisionmaking methodology, in order to set priorities for improvement plans to address the problems faced by the medical device distribution structure.

Results: The AHP analysis showed that supply stability was the most important factor, followed by greater transparency, efficiency, smart supply, and cost reduction.

Conclusions: It is necessary to establish a stable supply system and manage crises through supply stability, as well as to provide opportunities for fair trade through greater transparency. As steps towards those goals, we propose establishing a unique device identification system, an information disclosure system, online distribution, and a group purchasing organization system in Korea.
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http://dx.doi.org/10.5213/inj.1836152.076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6077940PMC
July 2018

Pharmacokinetics, Biodistribution, and Toxicity Evaluation of Anti-SEMA3A (F11) in Models.

Anticancer Res 2018 05;38(5):2803-2810

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Republic of Korea

Background/aim: The aim of our study was to investigate the pharmacokinetics (PK), tissue distribution and toxicity of F11 antibody to semaphorin 3A in mouse models and explore its anti-angiogenic and tumor-inhibitory effect.

Materials And Methods: Patient-derived xenograft (PDX) models were established via subcutaneous implantation of glioblastoma multiforme (GBM) cells and treated with F11.

Results: F11 significantly attenuated tumor growth and angiogenesis in the GBM PDX model. Within the range of administered doses, the PK of F11 in serum demonstrated a linear fashion, consistent with general PK profiles of soluble antigen-targeting antibodies. Additionally, the clearance level was detected at between 4.63 and 7.12 ml/d/kg, while the biological half-life was measured at 6.9 and 9.4 days. Tissue distribution of F11 in kidney, liver and heart was consistent with previously reported antibody patterns. However, the presence of F11 in the brain was an interesting finding.

Conclusion: Collectively, our results revealed angiogenic and tumor-inhibitory effect of F11 antibody and its potential therapeutic use within a clinical framework based on PK, biodistribution and toxicity evaluation in mouse models.
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http://dx.doi.org/10.21873/anticanres.12524DOI Listing
May 2018

Anti-SEMA3A Antibody: A Novel Therapeutic Agent to Suppress Glioblastoma Tumor Growth.

Cancer Res Treat 2018 Jul 10;50(3):1009-1022. Epub 2017 Nov 10.

Institute for Refractory Cancer Research, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Purpose: Glioblastoma (GBM) is classified as one of the most aggressive and lethal brain tumor. Great strides have been made in understanding the genomic and molecular underpinnings of GBM, which translated into development of new therapeutic approaches to combat such deadly disease. However, there are only few therapeutic agents that can effectively inhibit GBM invasion in a clinical framework. In an effort to address such challenges, we have generated anti-SEMA3A monoclonal antibody as a potential therapeutic antibody against GBM progression.

Materials And Methods: We employed public glioma datasets, Repository of Molecular Brain Neoplasia Data and The Cancer Genome Atlas, to analyze SEMA3AmRNA expression in human GBM specimens. We also evaluated for protein expression level of SEMA3A via tissue microarray (TMA) analysis. Cell migration and proliferation kinetics were assessed in various GBM patient-derived cells (PDCs) and U87-MG cell-line for SEMA3A antibody efficacy. GBM patient-derived xenograft (PDX) models were generated to evaluate tumor inhibitory effect of anti-SEMA3A antibody in vivo.

Results: By combining bioinformatics and TMA analysis, we discovered that SEMA3A is highly expressed in human GBM specimens compared to non-neoplastic tissues. We developed three different anti-SEMA3A antibodies, in fully human IgG form, through screening phage-displayed synthetic antibody library using a classical panning method. Neutralization of SEMA3A significantly reduced migration and proliferation capabilities of PDCs and U87-MG cell line in vitro. In PDX models, treatment with anti-SEMA3A antibody exhibited notable tumor inhibitory effect through down-regulation of cellular proliferative kinetics and tumor-associated macrophages recruitment.

Conclusion: In present study, we demonstrated tumor inhibitory effect of SEMA3A antibody in GBM progression and present its potential relevance as a therapeutic agent in a clinical framework.
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http://dx.doi.org/10.4143/crt.2017.315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056981PMC
July 2018

Antitumor activity, pharmacokinetics, tumor-homing effect, and hepatotoxicity of a species cross-reactive c-Met antibody.

Biochem Biophys Res Commun 2017 12 14;494(1-2):409-415. Epub 2017 Sep 14.

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, Republic of Korea; Institute for Refractory Cancer Research, Research Institute for Future Medicine, Samsung Medical Center, Seoul 06351, Republic of Korea; Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea. Electronic address:

The receptor tyrosine kinase c-Met plays critical roles in promoting tumor growth, invasion, metastasis, and angiogenesis in various types of cancer and is a promising therapeutic target. The development of a species cross-reactive therapeutic antibody could provide useful to comprehensive preclinical assessment in animal models. Towards this goal, we developed human/mouse cross-reactive c-Met antibodies using an antibody phage library. IRCR201, a c-Met antibody with species cross-reactivity, successfully inhibited the HGF/c-Met signaling pathway via degradation of c-Met and disruption of the binding with its partners, and demonstrated strong in vivo antitumor activity. In pharmacokinetic analysis, IRCR201 exhibited a nonlinear pharmacokinetic profile and showed rapid serum clearance at low dosage. Ex vivo fluorescence imaging and immunohistochemistry demonstrated strong tumor accumulation of IRCR201. Hepatotoxicity analysis revealed that IRCR201 does not significantly affect primary human and mouse hepatocytes. Serum chemistry analysis demonstrated that the alanine aminotransferase serum level was elevated in mice treated with 30 mg/kg IRCR201 than in PBS-treated mice, whereas the levels of aspartate aminotransferase and blood urea nitrogen did not significantly differ. Thus, IRCR201 is a potent therapeutic antibody that can disrupt the HGF/c-Met signaling axis and its species cross-reactivity would enable to evaluate precise biological activity in animal models.
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http://dx.doi.org/10.1016/j.bbrc.2017.09.061DOI Listing
December 2017

Tumor Inhibitory Effect of IRCR201, a Novel Cross-Reactive c-Met Antibody Targeting the PSI Domain.

Int J Mol Sci 2017 Sep 13;18(9). Epub 2017 Sep 13.

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, Korea.

Hepatocyte growth factor receptor (HGFR, c-Met) is an essential member of the receptor tyrosine kinase (RTK) family that is often dysregulated during tumor progression, driving a malignant phenotypic state and modulating important cellular functions including tumor growth, invasion, metastasis, and angiogenesis, providing a strong rationale for targeting HGF/c-Met signaling axis in cancer therapy. Based on its protumorigenic potentials, we developed IRCR201, a potent antagonistic antibody targeting the plexin-semaphorin-integrin (PSI) domain of c-Met, using synthetic human antibody phage libraries. We characterized and evaluated the biochemical properties and tumor inhibitory effect of IRCR201 in vitro and in vivo. IRCR201 is a novel fully-human bivalent therapeutic antibody that exhibits cross-reactivity against both human and mouse c-Met proteins with high affinity and specificity. IRCR201 displayed low agonist activity and rapidly depleted total c-Met protein via the lysosomal degradation pathway, inhibiting c-Met-dependent downstream activation and attenuating cellular proliferation in various c-Met-expressing cancer cells. In vivo tumor xenograft models also demonstrated the superior tumor inhibitory responsiveness of IRCR201. Taken together, IRCR201 provides a promising therapeutic agent for c-Met-positive cancer patients through suppressing the c-Met signaling pathway and tumor growth.
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http://dx.doi.org/10.3390/ijms18091968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618617PMC
September 2017

Natural killer (NK) cells inhibit systemic metastasis of glioblastoma cells and have therapeutic effects against glioblastomas in the brain.

BMC Cancer 2015 Dec 24;15:1011. Epub 2015 Dec 24.

Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul, 06351, South Korea.

Background: Glioblastoma multiforme (GBM) is characterized by extensive local invasion, which is in contrast with extremely rare systemic metastasis of GBM. Molecular mechanisms inhibiting systemic metastasis of GBM would be a novel therapeutic candidate for GBM in the brain.

Methods: Patient-derived GBM cells were primarily cultured from surgical samples of GBM patients and were inoculated into the brains of immune deficient BALB/c-nude or NOD-SCID IL2Rgamma(null) (NSG) mice. Human NK cells were isolated from peripheral blood mononucleated cells and expanded in vitro.

Results: Patient-derived GBM cells in the brains of NSG mice unexpectedly induced spontaneous lung metastasis although no metastasis was detected in BALB/c-nude mice. Based on the difference of the innate immunity between two mouse strains, NK cell activities of orthotopic GBM xenograft models based on BALB/c-nude mice were inhibited. NK cell inactivation induced spontaneous lung metastasis of GBM cells, which indicated that NK cells inhibit the systemic metastasis. In vitro cytotoxic activities of human NK cells against GBM cells indicated that cytotoxic activity of NK cells against GBM cells prevents systemic metastasis of GBM and that NK cells could be effective cell therapeutics against GBM. Accordingly, NK cells transplanted into orthotopic GBM xenograft models intravenously or intratumorally induced apoptosis of GBM cells in the brain and showed significant therapeutic effects.

Conclusions: Our results suggest that innate NK immunity is responsible for rare systemic metastasis of GBM and that sufficient supplementation of NK cells could be a promising immunotherapeutic strategy for GBM in the brain.
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http://dx.doi.org/10.1186/s12885-015-2034-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690248PMC
December 2015

GC1118, an Anti-EGFR Antibody with a Distinct Binding Epitope and Superior Inhibitory Activity against High-Affinity EGFR Ligands.

Mol Cancer Ther 2016 Feb 19;15(2):251-63. Epub 2015 Nov 19.

MOGAM Biotechnology Institute, Yongin, Gyeonggi-do, Republic of Korea.

The EGFR-targeted monoclonal antibodies are a valid therapeutic strategy for patients with metastatic colorectal cancer (mCRC). However, only a small subset of mCRC patients has therapeutic benefits and there are high demands for EGFR therapeutics with a broader patient pool and more potent efficacy. In this study, we report GC1118 exhibiting a different character in terms of binding epitope, affinity, mode of action, and efficacy from other anti-EGFR antibodies. Structural analysis of the EGFR-GC1118 crystal complex revealed that GC1118 recognizes linear, discrete N-terminal epitopes of domain III of EGFR, critical for EGF binding but not overlapping with those of other EGFR-targeted antibodies. GC1118 exhibited superior inhibitory activity against high-affinity EGFR ligands in terms of EGFR binding, triggering EGFR signaling, and proliferation compared with cetuximab and panitumumab. EGFR signaling driven by low-affinity ligands, on the contrary, was well inhibited by all the antibodies tested. GC1118 demonstrated robust antitumor activity in tumor xenografts with elevated expression of high-affinity ligands in vivo, whereas cetuximab did not. Considering the significant role of high-affinity EGFR ligands in modulating tumor microenvironment and inducing resistance to various cancer therapeutics, our study suggests a potential therapeutic advantage of GC1118 in terms of efficacy and a range of benefited patient pool. Mol Cancer Ther; 15(2); 251-63. ©2015 AACR.
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http://dx.doi.org/10.1158/1535-7163.MCT-15-0679DOI Listing
February 2016

Spatiotemporal Evolution of the Primary Glioblastoma Genome.

Cancer Cell 2015 Sep;28(3):318-28

Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea; Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology (SAIHST), Sungkyunkwan University, Seoul 06351, Korea; Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea. Electronic address:

Tumor recurrence following treatment is the major cause of mortality for glioblastoma multiforme (GBM) patients. Thus, insights on the evolutionary process at recurrence are critical for improved patient care. Here, we describe our genomic analyses of the initial and recurrent tumor specimens from each of 38 GBM patients. A substantial divergence in the landscape of driver alterations was associated with distant appearance of a recurrent tumor from the initial tumor, suggesting that the genomic profile of the initial tumor can mislead targeted therapies for the distally recurred tumor. In addition, in contrast to IDH1-mutated gliomas, IDH1-wild-type primary GBMs rarely developed hypermutation following temozolomide (TMZ) treatment, indicating low risk for TMZ-induced hypermutation for these tumors under the standard regimen.
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http://dx.doi.org/10.1016/j.ccell.2015.07.013DOI Listing
September 2015

USP1 targeting impedes GBM growth by inhibiting stem cell maintenance and radioresistance.

Neuro Oncol 2016 Jan 1;18(1):37-47. Epub 2015 Jun 1.

Department of Neurosurgery, Samsung Medical Center and Samsung Biomedical Research Institute, Seoul, Korea (J.-K.L., Y.Y., H.Y., W.K., D.-H.N.); Graduate School of Health Science & Technology, Samsung Advanced Institute for Health Science & Technology, Sungkyunkwan University, Seoul, Korea (N.C., H.C., Y.T.O., Y.Y., D.-H.N.); Department of Anatomy and Cell Biology, Sungkyunkwan University School of Medicine, Seoul, Korea (K.M.J.); Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio (E.K., Y.S., G.I.M., J.L.).

Background: Clinical benefits from standard therapies against glioblastoma (GBM) are limited in part due to intrinsic radio- and chemoresistance of GBM and inefficient targeting of GBM stem-like cells (GSCs). Novel therapeutic approaches that overcome treatment resistance and diminish stem-like properties of GBM are needed.

Methods: We determined the expression levels of ubiquitination-specific proteases (USPs) by transcriptome analysis and found that USP1 is highly expressed in GBM. Using the patient GBM-derived primary tumor cells, we inhibited USP1 by shRNA-mediated knockdown or its specific inhibitor pimozide and evaluated the effects on stem cell marker expression, proliferation, and clonogenic growth of tumor cells.

Results: USP1 was highly expressed in gliomas relative to normal brain tissues and more preferentially in GSC enrichment marker (CD133 or CD15) positive cells. USP1 positively regulated the protein stability of the ID1 and CHEK1, critical regulators of DNA damage response and stem cell maintenance. Targeting USP1 by RNA interference or treatment with a chemical USP1 inhibitor attenuated clonogenic growth and survival of GSCs and enhanced radiosensitivity of GBM cells. Finally, USP1 inhibition alone or in combination with radiation significantly prolonged the survival of tumor-bearing mice.

Conclusion: USP1-mediated protein stabilization promotes GSC maintenance and treatment resistance, thereby providing a rationale for USP1 inhibition as a potential therapeutic approach against GBM.
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http://dx.doi.org/10.1093/neuonc/nov091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4677407PMC
January 2016

In vivo RNAi screen identifies NLK as a negative regulator of mesenchymal activity in glioblastoma.

Oncotarget 2015 Aug;6(24):20145-59

Graduate School of Health Science & Technology, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Korea.

Glioblastoma (GBM) is the most lethal brain cancer with profound genomic alterations. While the bona fide tumor suppressor genes such as PTEN, NF1, and TP53 have high frequency of inactivating mutations, there may be the genes with GBM-suppressive roles for which genomic mutation is not a primary cause for inactivation. To identify such genes, we employed in vivo RNAi screening approach using the patient-derived GBM xenograft models. We found that Nemo-Like Kinase (NLK) negatively regulates mesenchymal activities, a characteristic of aggressive GBM, in part via inhibition of WNT/β-catenin signaling. Consistent with this, we found that NLK expression is especially low in a subset of GBMs that harbors high WNT/mesenchymal activities. Restoration of NLK inhibited WNT and mesenchymal activities, decreased clonogenic growth and survival, and impeded tumor growth in vivo. These data unravel a tumor suppressive role of NLK and support the feasibility of combining oncogenomics with in vivo RNAi screen.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652994PMC
http://dx.doi.org/10.18632/oncotarget.3980DOI Listing
August 2015

Targeting the epithelial to mesenchymal transition in glioblastoma: the emerging role of MET signaling.

Onco Targets Ther 2014 20;7:1933-44. Epub 2014 Oct 20.

Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University School of Medicine, Seoul, Korea.

Glioblastoma multiforme (GBM) is the most common human primary brain malignancy and has a dismal prognosis. Aggressive treatments using maximal surgical resection, radiotherapy, and temozolomide result in median survival of only 14.6 months in patients with GBM. Numerous clinical approaches using small molecule inhibitors have shown disappointing results because of the genetic heterogeneity of GBM. The epithelial to mesenchymal transition (EMT) is a crucial biological process occurring in the early development stages of many species. However, cancer cells often obtain the ability to invade and metastasize through the EMT, which triggers the scattering of cells. The hepatocyte growth factor (HGF)/MET signaling pathway is indicative of the EMT during both embryogenesis and the invasive growth of tumors, because HGF potently induces mesenchymal transition in epithelial-driven cells. Activation of MET signaling or co-overexpression of HGF and MET frequently represents aggressive growth and poor prognosis of various cancers, including GBM. Thus, efforts to treat cancers by inhibiting MET signaling using neutralizing antibodies or small molecule inhibitors have progressed during the last decade. In this review, we discuss HGF/MET signaling in the development of diseases, including cancers, as well as updates on MET inhibition therapy.
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http://dx.doi.org/10.2147/OTT.S36582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4211615PMC
November 2014

Antiangiogenic Therapy with Human Apolipoprotein(a) Kringle V and Paclitaxel in a Human Ovarian Cancer Mouse Model.

Transl Oncol 2014 Jun 17;7(3):368-76. Epub 2014 Jun 17.

Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA.

Introduction: The present study compared the effect of combination therapy using human apolipoprotein(a) kringle V (rhLK8) to conventional chemotherapy with paclitaxel for human ovarian carcinoma producing high or low levels of vascular endothelial growth factor (VEGF).

Materials And Methods: Human ovarian carcinoma cells producing high (SKOV3ip1) or low (HeyA8) levels of VEGF were implanted into the peritoneal cavity of female nude mice. Seven days later, mice were randomized into four groups: control (vehicle), paclitaxel [5 mg/kg, weekly intraperitoneal (i.p.) injection], rhLK8 (50 mg/kg, daily i.p. injection), or the combination of paclitaxel and rhLK8. Mice were treated for 4 weeks and examined by necropsy.

Results: In mice implanted with SKOV3ip1 cells, rhLK8 treatment had no significant effect on tumor incidence or the volume of ascites but induced a significant decrease in tumor weight compared with control mice. Paclitaxel significantly reduced tumor weight and ascites volume, and combination treatment with paclitaxel and rhLK8 had an additive therapeutic effect. Similarly, in HeyA8 mice, the effect of combination treatment on tumor weight and tumor incidence was statistically significantly greater than that of paclitaxel or rhLK8 alone. Immunohistochemical analysis showed a significant decrease in microvessel density and a marked increase of apoptosis in tumor and tumor-associated endothelial cells in response to combination treatment with paclitaxel and rhLK8.

Conclusion: Collectively, these results suggest that antiangiogenic therapy with rhLK8 in combination with taxane-based conventional chemotherapy could be effective for the treatment of ovarian carcinomas, regardless of VEGF status.
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http://dx.doi.org/10.1016/j.tranon.2014.04.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145395PMC
June 2014

Translational validation of personalized treatment strategy based on genetic characteristics of glioblastoma.

PLoS One 2014 1;9(8):e103327. Epub 2014 Aug 1.

Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea; Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea; Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul, Korea; Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Seoul, Korea.

Glioblastoma (GBM) heterogeneity in the genomic and phenotypic properties has potentiated personalized approach against specific therapeutic targets of each GBM patient. The Cancer Genome Atlas (TCGA) Research Network has been established the comprehensive genomic abnormalities of GBM, which sub-classified GBMs into 4 different molecular subtypes. The molecular subtypes could be utilized to develop personalized treatment strategy for each subtype. We applied a classifying method, NTP (Nearest Template Prediction) method to determine molecular subtype of each GBM patient and corresponding orthotopic xenograft animal model. The models were derived from GBM cells dissociated from patient's surgical sample. Specific drug candidates for each subtype were selected using an integrated pharmacological network database (PharmDB), which link drugs with subtype specific genes. Treatment effects of the drug candidates were determined by in vitro limiting dilution assay using patient-derived GBM cells primarily cultured from orthotopic xenograft tumors. The consistent identification of molecular subtype by the NTP method was validated using TCGA database. When subtypes were determined by the NTP method, orthotopic xenograft animal models faithfully maintained the molecular subtypes of parental tumors. Subtype specific drugs not only showed significant inhibition effects on the in vitro clonogenicity of patient-derived GBM cells but also synergistically reversed temozolomide resistance of MGMT-unmethylated patient-derived GBM cells. However, inhibitory effects on the clonogenicity were not totally subtype-specific. Personalized treatment approach based on genetic characteristics of each GBM could make better treatment outcomes of GBMs, although more sophisticated classifying techniques and subtype specific drugs need to be further elucidated.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0103327PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4118874PMC
April 2015

Vaccinia-based influenza vaccine overcomes previously induced immunodominance hierarchy for heterosubtypic protection.

Eur J Immunol 2014 Aug 16;44(8):2360-9. Epub 2014 Jun 16.

Vaccine II, Mogam Biotechnology Research Institute, Yongin Si, Republic of Korea.

Growing concerns about unpredictable influenza pandemics require a broadly protective vaccine against diverse influenza strains. One of the promising approaches was a T cell-based vaccine, but the narrow breadth of T-cell immunity due to the immunodominance hierarchy established by previous influenza infection and efficacy against only mild challenge condition are important hurdles to overcome. To model T-cell immunodominance hierarchy in humans in an experimental setting, influenza-primed C57BL/6 mice were chosen and boosted with a mixture of vaccinia recombinants, individually expressing consensus sequences from avian, swine, and human isolates of influenza internal proteins. As determined by IFN-γ ELISPOT and polyfunctional cytokine secretion, the vaccinia recombinants of influenza expanded the breadth of T-cell responses to include subdominant and even minor epitopes. Vaccine groups were successfully protected against 100 LD50 challenges with PR/8/34 and highly pathogenic avian influenza H5N1, which contained the identical dominant NP366 epitope. Interestingly, in challenge with pandemic A/Cal/04/2009 containing mutations in the dominant epitope, only the group vaccinated with rVV-NP + PA showed improved protection. Taken together, a vaccinia-based influenza vaccine expressing conserved internal proteins improved the breadth of influenza-specific T-cell immunity and provided heterosubtypic protection against immunologically close as well as distant influenza strains.
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http://dx.doi.org/10.1002/eji.201344005DOI Listing
August 2014

Characterization of CD45-/CD31+/CD105+ circulating cells in the peripheral blood of patients with gynecologic malignancies.

Clin Cancer Res 2013 Oct 6;19(19):5340-50. Epub 2013 Aug 6.

Authors' Affiliations: Mogam Biotechnology Research Institute, Yongin; Department of Biological Science, Sungkyunkwan University, Suwon; Department of Obstetrics and Gynecology, Cheil General Hospital and Women's Healthcare Center, Kwandong University College of Medicine, Seoul; Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea; and Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas.

Purpose: Circulating endothelial cells (CEC) have been widely used as a prognostic biomarker and regarded as a promising strategy for monitoring the response to treatment in several cancers. However, the presence and biologic roles of CECs have remained controversial for decades because technical standards for the identification and quantification of CECs have not been established. Here, we hypothesized that CECs detected by flow cytometry might be monocytes rather than endothelial cells.

Experimental Design: The frequency of representative CEC subsets (i.e., CD45(-)/CD31(+), CD45(-)/CD31(+)/CD146(+), CD45(-)/CD31(+)/CD105(+)) was analyzed in the peripheral blood of patients with gynecologic cancer (n = 56) and healthy volunteers (n = 44). CD45(-)/CD31(+) cells, which are components of CECs, were isolated and the expression of various markers (CD146, CD105, vWF, and CD144 for endothelial cells; CD68 and CD14 for monocytes) was examined by immunocytochemistry.

Results: CD45(-)/CD31(+)/CD105(+) cells were significantly increased in the peripheral blood of patients with cancer, whereas evaluation of CD45(-)/CD31(+)/CD146(+) cells was not possible both in patients with cancer and healthy controls due to the limited resolution of the flow cytometry. Immunocytochemistry analyses showed that these CD45(-)/CD31(+)/CD105(+) cells did not express vWF and CD146 but rather CD144. Furthermore, CD45(-)/CD31(+)/CD105(+) cells uniformly expressed the monocyte-specific markers CD14 and CD68. These results suggest that CD45(-)/CD31(+)/CD105(+) cells carry the characteristics of monocytes rather than endothelial cells.

Conclusions: Our data indicate that CD45(-)/CD31(+)/CD105(+) circulating cells, which are significantly increased in the peripheral blood of patients with gynecologic cancer, are monocytes rather than endothelial cells. Further investigation is required to determine the biologic significance of their presence and function in relation with angiogenesis.
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http://dx.doi.org/10.1158/1078-0432.CCR-12-3685DOI Listing
October 2013

Immunoglobulin Fc domain fusion to apolipoprotein(a) kringle V significantly prolongs plasma half-life without affecting its anti-angiogenic activity.

Protein Eng Des Sel 2013 Jun 9;26(6):425-32. Epub 2013 Apr 9.

Cancer Therapeutics Team, Mogam Biotechnology Research Institute, 341 Bojeong-dong, Giheung-gu, Yongin 449-910, Republic of Korea.

Angiogenesis is crucial for tumor growth and metastasis. Blocking this process is, therefore, a potentially powerful approach for the treatment of cancer. Human apolipoprotein(a) kringle V (rhLK8) is an angiogenesis inhibitor and is currently under development as an anti-cancer therapeutic. However, a relatively short in vivo half-life limits its widespread clinical use. This study was performed to evaluate whether fusion of an Fc domain to rhLK8 can extend plasma half-life. RhLK8-Fc fusion protein was expressed in CHO DG44 cells as a dimer and was readily purified by protein G affinity chromatography. The anti-angiogenic activity of rhLK8-Fc was similar to that of rhLK8, as determined by migration and tube formation assays with endothelial cells in vitro and a chorioallantoic membrane assay in vivo. Pharmacokinetic profiles in mice after single intravenous administration of rhLK8 or rhLK8-Fc showed that Fc fusion significantly increased the elimination half-life (t(½)) and the systemic exposure (AUC(inf)) of the protein, in parallel with a significant decrease in total clearance (CL). These data suggest that Fc fusion to rhLK8 is a powerful strategy for extending the plasma half-life of rhLK8 without affecting its anti-angiogenic activity, and could thus improve the clinical applicability of rhLK8.
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http://dx.doi.org/10.1093/protein/gzt015DOI Listing
June 2013

Evaluation of the efficacy of a pre-pandemic H5N1 vaccine (MG1109) in mouse and ferret models.

J Microbiol 2012 Jun 30;50(3):478-88. Epub 2012 Jun 30.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, 361-763, Republic of Korea.

The threat of a highly pathogenic avian influenza (HPAI) H5N1 virus causing the next pandemic remains a major concern. In this study, we evaluated the immunogenicity and efficacy of an inactivated whole-virus H5N1 pre-pandemic vaccine (MG1109) formulated by Green Cross Co., Ltd containing the hemagglutinin (HA) and neuraminidase (NA) genes of the clade 1 A/Vietnam/1194/04 virus in the backbone of A/Puerto Rico/8/34 (RgVietNam/04xPR8/34). Administration of the MG1109 vaccine (2-doses) in mice and ferrets elicited high HI and SN titers in a dose-dependent manner against the homologous (RgVietNam/04xPR8/34) and various heterologous H5N1 strains, (RgKor/W149/06xPR8/34, RgCambodia/04xPR8/34, RgGuangxi/05xPR8/34), including a heterosubtypic H5N2 (A/Aquatic bird/orea/W81/05) virus. However, efficient cross-reactivity was not observed against heterosubtypic H9N2 (A/Ck/Korea/H0802/08) and H1N1 (PR/8/34) viruses. Mice immunized with 1.9 μg HA/dose of MG1109 were completely protected from lethal challenge with heterologous wild-type HPAI H5N1 A/EM/Korea/W149/06 (clade 2.2) and mouse-adapted H5N2 viruses. Furthermore, ferrets administered at least 3.8 μg HA/dose efficiently suppressed virus growth in the upper respiratory tract and lungs. Vaccinated mice and ferrets also demonstrated attenuation of clinical disease signs and limited virus spread to other organs. Thus, this vaccine provided immunogenic responses in mouse and ferret models even against challenge with heterologous HPAI H5N1 and H5N2 viruses. Since the specific strain of HPAI H5N1 virus that would potentially cause the next outbreak is unknown, pre-pandemic vaccine preparation that could provide cross-protection against various H5 strains could be a useful approach in the selection of promising candidate vaccines in the future.
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http://dx.doi.org/10.1007/s12275-012-1573-zDOI Listing
June 2012

Repeated intravenous infusion of human apolipoprotein(a) kringle V is associated with reversible dose-dependent acute tubulointerstitial nephritis without affecting glomerular filtration function.

Toxicol Lett 2012 Aug 30;212(3):298-306. Epub 2012 May 30.

Cancer Biology Team, Mogam Biotechnology Research Institute, 341 Bojeong-dong, Giheung-gu, Yongin 446-799, Republic of Korea.

Because anti-angiogenic agents have shown various toxicities in clinical applications, the determination of their toxicities and their reversibility is important in the design of clinical trials. This study was performed to investigate the potential toxicities of an angiogenesis inhibitor, apolipoprotein(a) (Apo(a)) kringle V (rhLK8) in rats. Rats administered an intravenous (IV) bolus injection of rhLK8 (200 mg/kg) for 7 days showed significant increases in serum blood urea nitrogen (BUN), creatinine and the BUN/creatinine ratio, which was compatible with acute tubulointerstitial nephritis (TIN) in pathological examination. Because anti-angiogenic therapies are usually based on long-term treatment strategies, rats were administered 200 mg/kg/day of rhLK8 by intravenous infusion for 28 days. Rats receiving 200 mg/kg of rhLK8 showed abnormal serological and histologic findings, but their levels returned to within normal ranges 2 weeks after the cessation of administration. The creatinine clearance rate (CCr) was not affected by rhLK8 treatment. Collectively, our data indicate that the intravenous infusion of rhLK8 at therapeutic doses may induce renal toxicities, such as acute TIN, but these toxicities are clinically tolerable and reversible with close monitoring and a recovery period.
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http://dx.doi.org/10.1016/j.toxlet.2012.05.019DOI Listing
August 2012

Targeted antivascular therapy with the apolipoprotein(a) kringle V, rhLK8, inhibits the growth and metastasis of human prostate cancer in an orthotopic nude mouse model.

Neoplasia 2012 Apr;14(4):335-43

Cancer Biology Team, Mogam Biotechnology Research Institute, Yongin, Republic of Korea.

Antivascular therapy has emerged as a rational strategy to improve the treatment of androgen-independent prostate cancer owing to the necessity of establishing a vascular network for the growth and progression of the primary and metastatic tumor. We determined whether recombinant human apolipoprotein(a) kringle V, rhLK8, produces therapeutic efficacy in an orthotopic human prostate cancer animal model. Fifty thousand androgen-independent human prostate cancer cells (PC-3MM2) were injected into the prostate of nude mice. After 3 days, these mice were randomized to receive the vehicle solution (intraperitoneally [i.p.], daily), paclitaxel (8 mg/kg i.p., weekly), rhLK8 (50 mg/kg i.p., daily), or a combination of paclitaxel and rhLK8 for 4 weeks. Treatment with paclitaxel or rhLK8 alone did not show significant therapeutic effects on tumor incidence or on tumor size compared with the control group. The combination of rhLK8 and paclitaxel significantly reduced tumor size and incidence of lymph node metastasis. Significant reduction in microvessel density and cellular proliferation and induction of apoptosis of tumor cells, and tumor-associated endothelial cells, were also achieved. Similarly, PC-3MM2 tumors growing in the tibia showed significant suppression of tumor growth and lymph node metastasis by the combination treatment with rhLK8 and paclitaxel. The integrity of the bone was significantly preserved, and apoptosis of tumor cells and tumor-associated endothelial cells was increased. In conclusion, these results suggest that targeting the tumor microenvironment with the antivascular effect of rhLK8 combined with conventional cytotoxic chemotherapy could be a new and effective approach in the treatment of androgen-independent prostate cancer and their metastases.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349259PMC
http://dx.doi.org/10.1593/neo.12380DOI Listing
April 2012

Human apolipoprotein(a) kringle V inhibits ischemia-induced retinal neovascularization via suppression of fibronectin-mediated angiogenesis.

Diabetes 2012 Jun 16;61(6):1599-608. Epub 2012 Mar 16.

Mogam Biotechnology Research Institute, Yongin, Kyonggi-do, Republic of Korea.

Retinal neovascularization is observed in progression of diabetic retinopathy. New vessels grow into the vitreous cavity in proliferative diabetic retinopathy, resulting in traction retinal detachment and vitreous hemorrhage. To overcome the catastrophic visual loss due to these complications, efforts have been focused on the treatment of retinal neovascularization. In this study, we demonstrated the inhibitory effect of recombinant human apolipoprotein(a) kringle V (rhLK8) in an animal model of ischemia-induced retinal neovascularization. rhLK8 induced no definite toxicity on endothelial cells and retinal tissues at the therapeutic dosage. Interestingly, rhLK8 showed antiangiogenic effect, particularly on fibronectin-mediated migration of endothelial cells. Further experiments demonstrated high binding affinity of rhLK8 to α3β1 integrin, and suppression of it might be the mechanism of antiangiogenic effect of rhLK8. Furthermore, rhLK8 inhibited phosphorylation of focal adhesion kinase, resulting in suppression of activation of consequent p130CAS-Jun NH(2)-terminal kinase. Taken together, our data suggested the possible application of rhLK8 in the treatment of retinal neovascularization by suppression of fibronectin-mediated angiogenesis.
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http://dx.doi.org/10.2337/db11-1541DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357289PMC
June 2012

Sequencing and characterization of Varicella-zoster virus vaccine strain SuduVax.

Virol J 2011 Dec 16;8:547. Epub 2011 Dec 16.

Department of Microbiology, Chungbuk National University, Cheongju, South Korea.

Background: Varicella-zoster virus (VZV) causes chickenpox in children and shingles in older people. Currently, live attenuated vaccines based on the Oka strain are available worldwide. In Korea, an attenuated VZV vaccine has been developed from a Korean isolate and has been commercially available since 1994. Despite this long history of use, the mechanism for the attenuation of the vaccine strain is still elusive. We attempted to understand the molecular basis of attenuation mechanism by full genome sequencing and comparative genomic analyses of the Korean vaccine strain SuduVax.

Results: SuduVax was found to contain a genome that was 124,759 bp and possessed 74 open reading frames (ORFs). SuduVax was genetically most close to Oka strains and these Korean-Japanese strains formed a strong clade in phylogenetic trees. SuduVax, similar to the Oka vaccine strains, underwent T- > C substitution at the stop codon of ORF0, resulting in a read-through mutation to code for an extended form of ORF0 protein. SuduVax also shared certain deletion and insertion mutations in ORFs 17, 29, 56 and 60 with Oka vaccine strains and some clinical strains.

Conclusions: The Korean VZV vaccine strain SuduVax is genetically similar to the Oka vaccine strains. Further comparative genomic and bioinformatics analyses will help to elucidate the molecular basis of the attenuation of the VZV vaccine strains.
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http://dx.doi.org/10.1186/1743-422X-8-547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265557PMC
December 2011

Intranasal administration of a flagellin-adjuvanted inactivated influenza vaccine enhances mucosal immune responses to protect mice against lethal infection.

Vaccine 2012 Jan 31;30(2):466-74. Epub 2011 Oct 31.

Clinical Vaccine R&D Center, Chonnam National University, Gwangju 500-757, Republic of Korea.

The influenza virus, a mucosal pathogen that infects the respiratory tract, is a major global health issue. There have been attempts to mucosally administer inactivated influenza vaccines to induce both mucosal and systemic immune responses. However, mucosally administered inactivated influenza vaccine has low immunogenicity, which is partially due to the lack of an effective mucosal adjuvant. The development of a safe and effective mucosal adjuvant is a prerequisite to the practical use of a mucosal inactivated influenza vaccine. We have previously demonstrated that a bacterial flagellin, Vibrio vulnificus FlaB, when mixed with antigen and administered intranasally, exerts a strong mucosal adjuvant activity by stimulating the Toll-like receptor 5 (TLR5). In this study, we tested whether the FlaB protein could serve as an effective mucosal adjuvant for an inactivated trivalent influenza vaccine (TIV) manufactured for humans; in a murine vaccination model, this vaccine consists of A/Brisbane/59/07 (H1N1 subtype), A/Uruguay/716/07 (H3N2 subtype), and B/Florida/4/06 (B type). Intranasal co-administration of the TIV with FlaB induced prominent humoral responses as demonstrated by high influenza-specific IgA levels in both the mucosal secretions and serum and significant specific IgG induction in the systemic compartment. The FlaB protein significantly potentiated influenza-specific cytokine production by draining lymph node cells and splenocytes. The FlaB mucosal adjuvant conferred excellent protection against a lethal challenge with a live virulent virus with high hemagglutination inhibition (HAI) antibody (Ab) titers. The FlaB did not accumulate in the olfactory nerve and epithelium, guaranteeing against a retrograde uptake into the central nervous system. These results suggest that FlaB can be used as a promising mucosal adjuvant for nasal inactivated influenza vaccine development.
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http://dx.doi.org/10.1016/j.vaccine.2011.10.058DOI Listing
January 2012

Cell-cycle regulator Cks1 promotes hepatocellular carcinoma by supporting NF-κB-dependent expression of interleukin-8.

Cancer Res 2011 Nov 14;71(21):6827-35. Epub 2011 Sep 14.

New Biologics Team, Mogam Biotechnology Research Institute, Yongin, Kyonggi-do, Republic of Korea.

The cell-cycle regulator Cks1 has recently been implicated in Skp2-mediated ubiquitination of the tumor suppressor protein p27. In this article, we report that Cks1 exerts a Skp2-independent regulation of NF-κB that promotes interleukin-8 (IL-8) expression, which is critical to hepatocellular carcinoma (HCC) growth. Cks1 was upregulated frequently in human HCC tissues and cell lines. Cks1 knockdown in HCC cells elevated p27 levels and decreased tumorigenicity in a manner that was also associated with a strong downregulation of IL-8 expression. IL-8 downregulation was not phenocopied by either RNAi-mediated knockdown of Skp2 or ectopic overexpression of p27. However, attenuation of IL-8 expression itself was sufficient to blunt HCC growth. Mechanistic investigations revealed that IL-8 was controlled at a transcriptional level by Cks1 targeting of the NF-κB regulator IκBα, which led to NF-κB activation and IL-8 expression, through a p27-independent regulation of IκB kinase complex components. Collectively, our findings support the hypothesis that Cks1 supports hepatocarcinogenesis by NF-κB-mediated regulation of IL-8 expression, broadening the function of Cks1 in cancer beyond its role as a Skp2 cofactor in p27 ubiquitination.
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http://dx.doi.org/10.1158/0008-5472.CAN-10-4356DOI Listing
November 2011

Antiangiogenic kringles derived from human plasminogen and apolipoprotein(a) inhibit fibrinolysis through a mechanism that requires a functional lysine-binding site.

Biol Chem 2011 Apr 9;392(4):347-56. Epub 2011 Feb 9.

Cancer Biology Team, Mogam Biotechnology Research Institute, Yongin, Kyonggi-do, South Korea.

Many proteins in the fibrinolysis pathway contain antiangiogenic kringle domains. Owing to the high degree of homology between kringle domains, there has been a safety concern that antiangiogenic kringles could interact with common kringle proteins during fibrinolysis leading to adverse effects in vivo. To address this issue, we investigated the effects of several antiangiogenic kringle proteins including angiostatin, apolipoprotein(a) kringles IV(9)-IV(10)-V (LK68), apolipoprotein(a) kringle V (rhLK8) and a derivative of rhLK8 mutated to produce a functional lysine-binding site (Lys-rhLK8) on the entire fibrinolytic process in vitro and analyzed the role of lysine binding. Angiostatin, LK68 and Lys-rhLK8 increased clot lysis time in a dose-dependent manner, inhibited tissue-type plasminogen activator-mediated plasminogen activation on a thrombin-modified fibrinogen (TMF) surface, showed binding to TMF and significantly decreased the amount of plasminogen bound to TMF. The inhibition of fibrinolysis by these proteins appears to be dependent on their functional lysine-binding sites. However, rhLK8 had no effect on these processes owing to an inability to bind lysine. Collectively, these results indicate that antiangiogenic kringles without lysine binding sites might be safer with respect to physiological fibrinolysis than lysine-binding antiangiogenic kringles. However, the clinical significance of these findings will require further validation in vivo.
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http://dx.doi.org/10.1515/BC.2011.023DOI Listing
April 2011

Inhibition of the proliferation and invasion of hepatocellular carcinoma cells by lipocalin 2 through blockade of JNK and PI3K/Akt signaling.

Int J Oncol 2011 Feb 3;38(2):325-33. Epub 2010 Dec 3.

New Biologics Team, Mogam Biotechnology Research Institute, Yongin, Kyonggi-do 446-799, Republic of Korea.

Lipocalin 2 (Lcn2) has been reported to induce cellular proliferation based on its expression in a variety of proliferative cells. Consistent with these findings, the present study demonstrates a significant increase in Lcn2 levels in human hepatocellular carcinoma (HCC) tissues compared with non-tumor liver tissues. However, the role of Lcn2 in hepatocarcinogenesis is far from clear. To investigate the effects of Lcn2 expression on hepatocarcinogenesis, Chang liver and SK-Hep1 HCC cell lines were genetically manipulated to express Lcn2, and the effects on the proliferation and invasion of HCC cells were analyzed. Ectopic expression of Lcn2 in HCC cells significantly inhibited the growth of HCC cells in vitro and in vivo, reduced the invasive potential of cells, and inhibited the expression of matrix metalloproteinase 2 (MMP-2). Lcn2 may exert its function partly through the inhibition of the c-Jun N-terminal kinase (JNK) and phospha-tidyl inositol 3'-kinase (PI3K)/Akt signaling pathways in HCC cells. The selective inhibition of these pathways using pharmacological inhibitors significantly inhibited proliferation, invasion and MMP-2 expression, whereas Lcn2 expression suppressed the JNK and PI3K/Akt pathways. Collectively, these results clearly indicate that Lcn2 may play a protective role against the progression of HCCs by suppressing cell proliferation and invasion. The clinical significance of the present findings should be evaluated further.
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http://dx.doi.org/10.3892/ijo.2010.854DOI Listing
February 2011
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